1. Field of the Invention
This invention relates to underbed thread trimmers for sewing machines which have picking arms for grasping the bobbin thread and holding it so that a proper stitch may be formed after the completion of the thread cutting cycle.
2. Description of the Prior Art
Sewing machine underbed thread trimmers are known which have picking arms which are driven across the face of the looptaker to engage and manipulate the needle thread during the thread cutting cycle. See for example the U.S. Pat. No. 3,776,161 which issued to Papajewski et al, on Dec. 4, 1973, the rights to which are assigned to the assignee of this invention and the teachings of which are incorporated herein by reference.
One problem with some formerly disclosed underbed thread trimmers is that the picking arm did not positively engage the bobbin thread and restrain it after the thread had been severed to facilitate the subsequent formation of lockstitches.
Another problem is that the thread engaging extremity of the picking arm was not designed to encourage the capture of one limb of the needle thread and the bobbin thread.